1. Technical Field
This invention relates to ultrasonic surgical systems and, more particularly, to an improved apparatus for facilitating the performance of surgical procedures such as simultaneous soft tissue dissection and cauterization of large and small blood vessels through the use of a precisely controlled ultrasonically vibrating instrument, such as a blade or scalpel.
2. Background
It is known that electric scalpels and lasers can be used as surgical instruments to perform the dual function of simultaneously effecting the incision and hemostatis of soft tissue by cauterizing tissues and blood vessels. However, such instruments employ very high temperatures to achieve coagulation, causing vaporization and fumes as well as splattering. Additionally, the use of such instruments often results in relatively wide zones of thermal tissue damage.
Cutting and cauterizing of tissue by means of surgical blades vibrated at high speeds by ultrasonic drive mechanisms is also well known. In such systems, an ultrasonic generator is provided which produces an electrical signal of a particular voltage, current and frequency, e.g., 55,500 cycles per second. The generator is connected by a cable to a handpiece, which contains piezoceramic elements forming an ultrasonic transducer. In response to a switch on the handpiece or a foot switch connected to the generator by another cable, the generator signal is applied to the transducer, which causes a longitudinal vibration of its elements. A structure connects the transducer to a surgical blade, which is thus vibrated at ultrasonic frequencies when the generator signal is applied to the transducer. The structure is designed to resonate at the selected frequency, thus amplifying the motion initiated by the transducer.
The blade is often non-symmetrical in shape and, during the surgical procedure, the physician manipulates the handpiece to cause the blade to contact the tissue to be treated. Because the switch which controls operation of the blade is disposed on the handpiece, the location of the switch may at times prevent the physician from contacting tissue with the desired orientation of the blade because the relative position between the switch and the blade may prevent or render it difficult for the physician to manipulate the blade to the proper position while still being able to activate the switch with his/her fingers.
Thus, there is a need for a handpiece and switch assembly which will permit the physician to freely access tissue and operate thereon without having to worry about the relative position between the switch and the blade.